The Effect of Tubing Shapes on Frame Aerodynamics
Both the size and shape of bicycle frame tubing has a significant impact on the frame’s aerodynamic drag, with streamlined and airfoil-shaped tubing generally having less air resistance than nearly any other shape, also, a thin airfoil section will nearly always generate less drag than a thick airfoil section, provided the length of the airfoil is constant. The coefficients of drag(cd) for several test shapes are provided below. (all test shapes have the same frotal area)
These test examples show that the shape plays a very important role in aerodynamics. The triangle shape, while having the same frontal area as the plate shape, has 10% less drag than the plate due to the improved aerodynamic shape of it is downwind side.
When you compare bike frames, you cannot take each one of them to a wind tunnel for individual testing. But you can study the way the frame is designed.
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| Frame Tube Comparison |
Downtube dimensions
(Aspect Ratio = Length / Width) |
| Frame |
Length |
Width |
Aspect Ratio |
| CEEPO VENOM |
80 |
26 |
3.08 |
| CERVELO P3C |
81 |
29 |
2.79 |
| CERVELO P2C |
81 |
29 |
2.79 |
| CANNONDALE SLICE |
79 |
31 |
2.55 |
| LOOK 496 |
78 |
31 |
2.52 |
| SPECIALIZED TRANSITION |
74 |
30 |
2.47 |
| CEEPO STINGER |
70 |
30 |
2.33 |
| QR LUCERO |
67 |
29 |
2.31 |
| KESTREL AIRFOIL PRO |
75 |
37 |
2.03 |
| PINARELLO CRONO |
61 |
31 |
1.97 |
| BMC TT02 |
64 |
33 |
1.94 |
| CALDORA PHX |
70 |
36 |
1.94 |
| KUOTA KALIBUR |
72 |
38 |
1.89 |
| ORBEA ORDU |
75 |
40 |
1.88 |
| SCOTT PLASMA |
74 |
45 |
1.64 |
| PINARELLO MONTELLO |
71 |
44 |
1.61 |
| KUOTA K-FACTOR |
56 |
38 |
1.47 |
